Toner dispensing apparatus

ABSTRACT

A toner dispensing apparatus including a toner supply container having a discharge opening obturated by two parallel rollers forming a nip and rotating in the same direction and at the same speed and a further roller below the two rollers which rotates at a speed in excess of the speed of the two rollers to remove toner from the two rollers. The roller rotating in the direction of the nip for toner supply has left and right hand helical grooves.

United States Patent 1191 Schon Se t. 17 1974 [54] TONER DISPENSING APPARATUS FOREIGN PATENTS OR APPLICATIONS lnvemorl Klaus Peter $6110", 14, 1,473,211 5/1970 Germany 222/414 Rathenauplatz, 1,271,036 6/1968 Germany Wiesbaden-Biebrich, Germany 185.913 10/1917 Germany 222/414 [22] filed: 1972 Primary Examiner-Stan1ey H. Tollberg [21] Appl. No.: 298,815 Assistant Examiner-Norman L. Stack, Jr.

Attorney, Agent, or Firm-Stevens, Davis, Miller & [30] Foreign Application Priority Data Mosher Oct. 22, 1971 Germany 2152592 ABSTRACT 52 US. Cl. 222/414, 222/DIG. 1 A toner dispensing apparatus including a toner Supply 51 1111.01. GOlt 11/46 Container having a discharge Opening obwrated by [58] Field of Search 222/DIG 1 414 342 352 two parallel rollers forming a nip and rotating in the 222/367 6 29/12l same direction and at the same speed and a further roller below the two rollers which rotates at a speed in [56] References Cited excess of the speed of the two rollers to remove toner UNITED STATES PATENTS from the two rollers. The roller rotating in the direction of the nip for toner supply has left and right hand 2,321,082 6/1943 Harshberger 222/414 X helical grooves 3,376,854 4/1968 Kamola ZZZ/DIG. 1 3,637,112 1/1972 Christy 222/342 8 Claims, 2 Drawing Flgures 2 5 g 5; It n a r MOTOR Q 1 TONER DISPENSING APPARATUS This invention relates to a toner dispensing apparatus.

In electrophotographic reproduction machines, toner is continuously used up in making the copies. Depending upon the size of the developer tank and upon the number and density of the copies, the images become faint after varying periods of time. This has proved particularly troublesome in the case of high-speed machines, and it has therefore been necessary to provide apparatus for dispensing further amounts of toner.

An apparatus of this kind for dispensing toner is disclosed for example in German Patent Specification 1,939,997, as published. In this apparatus a roller having a longitudinal groove is provided in the bottom of a supply container for the toner. This apparatus has proved reliable in service, but some toner material forms so-called bridges in the supply container and this adversely affects the dispensing of the toner.

The present invention provides a toner dispensing apparatus including a supply container for the toner, which container has at its lower end a discharge opening obturated by two parallel rollers forming a nip but adapted to rotate in the same direction, the roller arranged to move upward at the nip having a smooth surface and the roller arranged to move downward at the nip having a right hand and a left hand helical groove for transporting toner from the supply container,

means being provided below the nip for removing toner from the grooves, thereby allowing it to fall freely.

The apparatus of the invention is suitable for use with various types of toner, is reliable and accurate in operation and in particular prevents bridging.

At the nip the two parallel rollers may be in contact with one another or separated by a very narrow gap corresponding to the average diameter of the toner particles.

The invention is illustrated by way of example in the accompanying drawing, in which:

FIG. 1 is a diagrammatic section through a toner dispensing apparatus, and

FIG. 2 is a plan view of one of the rollers of FIG. 1.

Referring to FIG. 1, toner material 1 is accommodated in a supply container which is bounded by vertical walls 2. A discharge opening 3 at the lower end of the supply container is obturated by two rollers 4 and 5 arranged to form a nip through which toner passes and which, with the aid of a drive means, not illustrated, can be rotated in the same direction as shown by the arrows. A stripping felt 6 is fitted as shown to one of the walls 2 of the supply container. The stripping felt 6 is provided to prevent the roller 5, which near the wall 2 of the container rotates away from the container, from entraining small particles of toner. Below the two rollers 4 and 5 is a brush roller 7 which can be caused to rotate in the same direction as the rollers 4 and 5 by a drive likewise.

The roller 5 is made of smooth polished hardchromium plated steel, whereas the roller 4 has dispensing grooves as shown in FIG. 2. The toner dispensing roller 4 has a right-hand and a left-hand helical groove 8, the two grooves crossing each other. In the roller 4, the pitch of each of the helical grooves corresponds to the diameter of the roller.

When the apparatus is operating, the rollers 4, 5 and 7 are either rotated continuously, or their rotation is intermittent and controlled by a signal which is sent by a device, not illustrated, when a certain quantity of toner has been used up, i.e., when a certain degree of toner-impoverishment occurs. The roller 4, in its rotation, entrains toner in its helical grooves. Since the grooves 8 are opposite helices, rotation of the toner dispensing roller 4 does not cause the toner to be carried towards either of its ends, owing to the fact that portions of the grooves constantly move to the left and to the right within the supply container. It has been found that this principle results in reliable and trouble-free dispensing of toner. The brush roller 7 sweeps out the grooves in the dispensing roller 4 and enables the dispensed toner material to fall freely, for example into a developer tank of an electrophotographic reproduction machine, which tank is located below the apparatus illustrated in FIG. 1.

A common drive means may be used, which rotates the nip rollers at the same speed and the brush roller in excess of that speed, e.g., at twice that speed.

What is claimed is:

1. A toner dispenser including a supply container for the toner dispenser, said container having at its lower end a discharge opening obturated by two parallel rollers at the terminus of the discharge passage forming a nip to receive toner by gravity through the discharge outlet and generally horizontal for rotation,

means for rotating,

the roller arranged to move upward at the nip having a smooth surface and the roller arranged to move downward at the nip having a right hand and a left hand helical groove of sufficient depth to receive said toner extending across the length of the discharge passage which is obturated by the rollers on exposure to the discharge outlet for transporting toner from the supply container,

said roller arranged to move downwardly having a smooth surface except for said grooves, and means being provided below the nip for removing toner from said grooves.

2. The apparatus of claim 1 in which the two helical grooves are of the same pitch and the same depth.

3. The apparatus of claim 1 in which the grooves are of arcuate cross-section.

4. The apparatus of claim 1 in which the pitch of the helical grooves corresponds substantially to the diameter of the roller.

5. The apparatus of claim 1 in which the opening in the container is defined in the axial direction of the rollers by walls extending vertically upwards.

6. The apparatus of claim 1 in which the toner removal means is a brush roller rotatable in the same direction as the nip rollers and of which the brush means makes contact with both nip rollers.

7. The apparatus of claim 6 in which the said drive means is also adapted to rotate the brush roller at a speed in excess of the speed of the nip rollers.

8. The apparatus of claim 1 including common drive means for rotating the nip rollers at the same speed. 

1. A toner dispenser including a supply container for the toner dispenser, said container having at its lower end a discharge opening obturated by two parallel rollers at the terminus of the discharge passage forming a nip to receive toner by gravity through the discharge outlet and generally horizontal for rotation, means for rotating, the roller arranged to move upward at the nip having a smooth surface and the roller arranged to move downward at the nip having a right hand and a left hand helical groove of sufficient depth to receive said toner extending across the length of the discharge passage which is obturated by the rollers on exposure to the discharge outlet for transporting toner from the supply container, said roller arranged to move downwardly having a smooth surface except for said grooves, and means being provided below the nip for removing toner from said grooves.
 2. The apparatus of claim 1 in which the two helical grooves are of the same pitch and the same depth.
 3. The apparatus of claim 1 in which the grooves are of arcuate cross-section.
 4. The apparatus of claim 1 in which the pitch of the helical grooves corresponds substantially to the diameter of the roller.
 5. The apparatus of claim 1 in which the opening in the container is defined in the axial direction of the rollers by walls extending vertically upwards.
 6. The apparatus of claim 1 in which the toner removal means is a brush roller rotatable in the same direction as the nip rollers and of which the brush means makes contact with both nip rollers.
 7. The apparatus of claim 6 in which the said drive means is also adapted to rotate the brush roller at a speed in excess of the speed of the nip rollers.
 8. The apparatus of claim 1 including common drive means for rotating the nip rollers at the same speed. 